Implants for enhanced anchoring within bone

ABSTRACT

Implants for anchoring within bone are provided herein. An implant may include at least one thread extending around a core in a plurality of turns from the coronal region to the apical region. The thread(s) has a thread outer diameter that may define a cylindrical portion, wherein the thread outer diameter remains constant for more than one turn around the core, and define a conical portion, wherein the thread outer diameter decreases at a thread diameter decrease rate in the apical direction. The thread(s) may have a plurality of notches spaced radially and longitudinally from one another. The notches may be partially notched to reflect a portion of a semi-spherical surface and partially notched to reflect a portion of a semi-cylindrical surface.

I. CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/874,145, filed Oct. 2, 2015, now U.S. Pat. No. 9,681,930, whichclaims the benefit of priority to Brazilian Patent Application No. 102014 031426 1, filed Dec. 15, 2014, the entire contents of each of whichare incorporated herein by reference.

II. TECHNICAL FIELD

This technology generally relates to implants for anchoring within bone,such as Osseointegrated dental implants.

III. BACKGROUND

Osseointegrated implants may be used to anchor prosthetic structures,bone substitutes, or corrective elements on the human skeleton. Forexample, dental and orthopedic Osseointegrated implants in the form ofscrews may be anchored to the jawbone via the mouth to supportprosthetic substitutes for one or more missing, lost, removed, ordamaged teeth. As another example, screw implants may be installed onthe spinal column for the fixation of bars to support and spacevertebrae.

Bones are generally made of a rigid outer layer and a vascularizedspongy core. The thickness of each of these rigid and spongy regions isparticular to the biology of each person. During installation of animplant, however, it is expected that part of the implant will remain inthe rigid region and part in the spongy region. To increase thestability of the implant after installation, and to reduce the patient'shealing time, both the amount of bone removed and the damage to theblood vessels in proximity to the implant should be minimized duringinstallation.

Most implants available on the market are formed of a cylindrical,generally screw-shaped body adapted for insertion into the bone. Thecylinder is usually made from a biocompatible metal, such as titaniumand alloys thereof, and may be coated with other types of biocompatiblematerials, such as hydroxyapatite, and/or receive a surface treatment inorder to improve the osseointegration quality of the surface.

The different implants often diverge in the characteristics and geometryof their threads, as persons in the art seek to improve the quality ofimplant engagement with the bone structure.

U.S. Pat. No. 8,029,285 to Holman describes an implant generally in theform of a threaded cylinder having a prosthetic interface at its upperend, also known as the coronal end. At the lower end of the implant,also known as the apical end, there is a cut that runs through multiplethreads, forming a self-tapping structure. Upon inserting implants withthis type of structure, the lower part tends to accumulate bonematerial, which makes it difficult for the cut material to exit, leadingto a loss of the self-tapping effect. The same implant further includesa slight increase in the diameter of the cylindrical body in the coronalregion. Such increase is intended to compress the rigid region of thebone at the final moment when installing the implant, with the intentionof increasing stability after installation. There are significantdrawbacks to use of the implant designs in Holman such as theaccumulation of material and fluids in the bone cavity during theinstallation of the implant that can lead to osseointegration issues,resulting in extended healing time.

There have been attempts to reduce such accumulation of material andfluids in bone during installation. For example, EP 0 895 757 B1 toCorigliani describes providing drainage channels along with a body whosecore to gradually compress the bone without retaining fluids.

U.S. Pat. No. 8,714,977 to Fromovich describes a dental implant thatfacilitates insertion including a body having a coronal end and anapical end opposite the coronal end. An implant-prosthetic interfaceregion is provided adjacent the coronal end. A tapered region isadjacent the apical end. A variable profile helical thread extends alongthe tapered region. The thread becomes broader in the apical-coronaldirection and higher in the coronal-apical direction. The threadsinclude an apical side, a coronal side and a lateral edge connectingthem. The variable profile thread includes an expanding length of thelateral edge while the distance of the lateral edge from the base isreduced in the direction of the coronal end. The implant also has agradual compressing tapered core, a self-drilling apical end with aspiral tap, and a coronal end with and inverse tapering.

The use of a conical core permits insertion of the implant into a boreof smaller diameter, which will be widened during the insertion,preserving a larger amount of bone around the implant. The conical corefurther has the advantage of compressing the bone during installation,increasing the stability after insertion thereof. However, the use ofwide threads makes it difficult to align the implant in the bore at theinitial moment of insertion, which may call for adjustment duringinsertion leading to the undesirable result of increased bone loss.Excessively wide threads from conventional designs also may causeproblems when the space for insertion of the implant is limited by theroots of adjacent teeth—especially in the molar region, where rootsextend sideways, and cutting the root of a healthy tooth with theimplant thread would damage, and may even lead to the loss of, thetooth. Furthermore, a wide thread cuts a larger amount of thevascularization around the implant region, which delays healing.

Additionally, the continuously cut self-tapping structure concentratedin the apical portion of conventional implants suffers from drawbacks ofaccumulation of material within the self-tapping structure, increasingrisks of osseointegration issues leading to extended healing time.

IV. SUMMARY

Implants are provided herein that are designed to minimize bone lossduring installation as compared to conventional implants. The implantsfacilitate proper orientation during installation and minimize damage tothe blood vessels surrounding the implant region, while improving thestability of the implant after installation. The implants providedherein may include a self-drilling thread geometry that distributes boneremoval structure along the length of the implant with radiallyspaced-apart curved cut cavities. The implants also may have a highdiameter-profile configuration, which provides the greatest thread widthin the central region (e.g., about midway point of implant, within 10%of the midway point of implant, within 20% of the midway point ofimplant, within 30% of the midway point of implant) of the implantlengthwise and the thread width need not increase thereafter in thecoronal direction.

In accordance with one aspect, an implant for anchoring within bone(e.g., jawbone) is provided. The implant may include a coronal regionhaving a coronal end and an apical region having an apical end, theapical end opposite the coronal end. The implant also may have a core, aprosthetic interface, and at least one thread. The core may extend fromthe coronal region to the apical region. The core may have a core outerdiameter that decreases at a core diameter decrease rate in an apicaldirection towards the apical end. The prosthetic interface is preferablyat the coronal region (e.g., partially or fully). The at least onethread may extend around the core in a plurality of turns from thecoronal region to the apical region. The at least one thread has athread outer diameter that may be configured to define a cylindricalportion, wherein the thread outer diameter remains constant for morethan one turn around the core, and to define a conical portion, whereinthe thread outer diameter decreases at a thread diameter decrease ratein the apical direction. The thread diameter decrease rate may begreater than the core diameter decrease rate.

The cylindrical portion and the conical portion may meet at aninflection point. The thread height of the at least one thread may begreater at turns adjacent (e.g., immediately adjacent) the inflectionpoint than turns adjacent (e.g., immediately adjacent) the coronal andapical ends. The thread width of the at least one thread may be greaterat turns adjacent (e.g., immediately adjacent) the coronal and apicalends than turns adjacent (e.g., immediately adjacent) the inflectionpoint. The implant may have two threads extending around the core in adouble-thread configuration.

The apical end may have a rounded shape and may extend beyond the atleast one thread an extension distance (e.g., between 0.1 and 0.7 mm) inthe apical direction.

The coronal region adjacent the coronal end may include one or moreconcave rings. At least a portion of the coronal region may have afrustoconical shape with decreasing size in a coronal direction.

The prosthetic interface is preferably configured for coupling to aprosthetic (e.g., crown, bridge, abutment). The prosthetic interface mayinclude a Morse taper connection, internal threads, and/or ananti-rotation coupling in a polygon (e.g., hexagon) shape. Theprosthetic interface may be adapted for direct coupling to a bridge orcrown.

In accordance with another aspect, an implant for anchoring within bone(e.g., jawbone) is provided. The implant may include a coronal regionhaving a coronal end and an apical region having an apical end, theapical end opposite the coronal end. The implant also may have a core, aprosthetic interface, and at least one thread. The core may extend fromthe coronal region to the apical region. The prosthetic interface ispreferably at the coronal region (e.g., partially or fully). The atleast one thread may extend around the core in a plurality of turns fromthe coronal region to the apical region and the at least one thread mayhave a plurality of curved notches that may each define a cutting edge.A first curved notch on a first turn need not substantially overlap witha second curved notch on a second turn, the second turn being adjacentthe first turn in a coronal direction. The first curved notch need notsubstantially overlap with a third curved notch on a third turn, thethird turn being adjacent the first turn in an apical direction. Theoverlap, if any, of the second and third curved notches with the firstcurved notch is preferably at opposing ends of the first curved notch.

The plurality of curved notches may each be partially notched to reflecta portion of a semi-spherical surface. The plurality of curved notchesmay each be partially notched to reflect a portion of a semi-cylindricalsurface. The semi-spherical notch may intersect with thesemi-cylindrical notch at each of the curved notches.

The second turn may be immediately adjacent the first turn in thecoronal direction and the third turn may be immediately adjacent thefirst turn in the apical direction. In some embodiments, the firstcurved notch on the first turn does not overlap with the second curvednotch on the second turn by more than 20% a width of the first curvednotch (e.g., at one side of the first curved notch) and the first curvednotch on the first turn does not overlap with the third curved notch onthe third turn by more than 20% the width of the first curved notch(e.g., at an opposing side of the first curved notch). The first curvednotch need not overlap with the second curved notch and need not overlapwith the third curved notch.

In accordance with another aspect, an implant for anchoring within bone(e.g., jawbone) is provided. The implant may include a coronal regionhaving a coronal end and an apical region having an apical end, theapical end opposite the coronal end. The implant also may have a core, aprosthetic interface, and at least one thread. The core may extend fromthe coronal region to the apical region. The prosthetic interface ispreferably at the coronal region (e.g., partially or fully). The atleast one thread may extend around the core in a plurality of turns fromthe coronal region to the apical region. The at least one thread mayinclude a plurality of curved notches that may each define a cuttingedge. In some embodiments, at least one of the plurality of curvednotches is partially notched to reflect a portion of a semi-sphericalsurface and partially notched to reflect a portion of a semi-cylindricalsurface. The semi-spherical notch may intersect with thesemi-cylindrical notch.

Provided herein are methods of inserting the implants described abovewithin bone. In accordance with one aspect, a method may includepositioning an apical end of the implant at a desired location of thebone (e.g., at a predrilled bore hole in the jawbone where a prostheticis to be placed to replace one or more teeth). The implant may have atleast one thread extending around a core of the implant in a pluralityof turns. The at least one thread may have a plurality of curved notcheseach defining a cutting edge where a partially semi-spherically curvedportion of the notch meets the outer surface of the at least one thread.The method may further include rotating the implant (e.g., clockwise)such that the at least one thread cuts the bone contacted by the atleast one thread to enlarge an opening in the bone as the implant isscrewed into the bone. The at least one thread may have a self-drillingconfiguration (e.g., at least where the thread(s) begins at or adjacentthe apical end of the implant) to compress bone as the implant isinstalled. During installation, the method may include applying acounter-torque by rotating the implant in the opposite direction (e.g.,counterclockwise) to cut bone with at least one cutting edge. Suchcounter-torque rotation may be especially advantageous for removingdense/hard bone tissue encountered during installation. For example, thedentist/surgeon may apply the counter-torque to cut and remove thehard/dense bone material at a partial installation position beforereaching the desired, full installation depth in the bone because, forexample, the implant becomes stuck during installation. Aftercounter-torque rotation, the method may include rotating the implant inthe installation direction (e.g., clockwise) to complete installation.The method may also include repeating counter-torque rotation one ormore additional times during installation at the same depth or adifferent depth(s) as the depth of the first counter-torque rotation.After installation, a prosthetic (e.g., crown, abutment, bridge) may becoupled to the implant directly or via an intermediate element such asan abutment.

In accordance with another aspect, a method may include positioning anapical end of the implant at a desired location of the bone (e.g., at apredrilled bore hole in the jawbone where a prosthetic is to be placedto replace one or more teeth). The implant may include at least onethread extending around a core of the implant in a plurality of turns.The at least one thread may have a thread outer diameter configured todefine a cylindrical portion and a conical portion formed more apicallythan the cylindrical portion along a length of the implant. The methodmay further include rotating the implant such that the conical portionof the at least one thread increases an opening diameter in the bone asthe conical portion enters the bone until the conical portion is fullyscrewed into the bone. The method also may include continuing to rotatethe implant such that the cylindrical portion of the at least one threadenters the bone without increasing the opening diameter in the bone. Thecylindrical portion outer diameter may be equal to the maximum outerdiameter of the conical portion. In addition, the cylindrical portionmay be formed along at least 25% of the length of the thread.

V. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a cross-sectional view of an embodiment of an exemplaryimplant constructed in accordance with the principles of the presentdisclosure.

FIG. 1B illustrates a side view of the implant shown in FIG. 1A.

FIG. 1C shows a cross-sectional view of the implant along line AA inFIG. 1B, including details of the notches.

FIG. 1D illustrates a close-up view of a curved notch for use in theimplant of FIG. 1A.

FIG. 1E illustrates a frustoconical portion, a prosthetic interfaceportion, a core portion, and threads of the implant of FIG. 1A separatedfrom one another for illustrative purposes.

FIG. 1F shows details of the thread design of the implant of FIG. 1A.

FIGS. 1G, 1H, and 1I show top, isometric, and side views, respectively,of the implant of FIG. 1A.

FIGS. 2A, 2B, and 2C show top, isometric, and side views, respectively,of an alternative embodiment of an exemplary implant constructed inaccordance with the principles of the present disclosure.

FIGS. 3A, 3B, and 3C show top, isometric, and side views, respectively,of an another embodiment of an exemplary implant constructed inaccordance with the principles of the present disclosure, including aprosthetic interface in the form of an external hexagon.

FIGS. 4A, 4B, and 4C show top, isometric, and side views, respectively,of an yet another embodiment of an exemplary implant constructed inaccordance with the principles of the present disclosure, wherein a partof the prosthetic geometry is integral with the implant in a one-pieceimplant manner.

VI. DETAILED DESCRIPTION OF THE INVENTION

Osseointegrated implants are provided herein that may be used to anchorprosthetic structures, bone substitutes, and/or corrective elements onthe human skeleton. The implants may be dental Osseointegrated implantsin the form of screws designed to be anchored to the jawbone via themouth to support prosthetic substitutes for one or more missing, lost,removed, and/or damaged teeth.

Referring now to FIG. 1A, a cross-sectional view of an exemplary implantconstructed in accordance with the principles of the present disclosureis provided. Implant 100 is adapted for anchoring within bone. In apreferred embodiment, implant 100 is a dental Osseointegrated implantadapted for anchoring within the jawbone via the mouth to supportprosthetic substitutes for one or more missing, lost, removed, and/ordamaged teeth.

Implant 100 may include coronal region 101, apical region 102, and core103 extending from coronal region 101 to apical region 102. Coronalregion 101 is at the upper portion of implant 100 and includes coronalend 104 at the upper most end, while apical region 102 is at the lowerportion of implant and includes apical end 105 at the lower most end,opposite coronal end 104. Apical region 102 is adapted for insertioninto bone prior to coronal region 101. Apical end 105 may be firstinserted into the bone and implant 100 then is screwed down to theproper depth using, for example, drilling tools adapted to engage aportion of implant 100 at coronal region 101. Apical end 105 may beflat, but preferably has a rounded shape to minimize damage to the Sinusmembrane if implant 100 is advanced excessively during installation.Further, in order to prevent damages, apical end 105 extends in anapical direction AD an amount beyond the beginning of the implantsthread(s), e.g., between 0.1 and 0.7 mm, between 0.25 and 0.5 mm.

Implant 100 may be screwed such that coronal end 104 of coronal region101 is beneath, flush with, or above the outer bone surface, andpreferably coronal end 104 remains exposed for subsequent installationof the component(s) (e.g., abutment, crown, bridge) that will beanchored on implant. Coronal region 101 of implant 100 may includefrustoconical portion 106 tapering in the coronal direction CD such thatthe outer diameter at frustoconical portion 106 decreases in the coronaldirection CD at frustoconical angle 107 (e.g., between 1 and 60°,between 1 and 45°, between 1 and 30°, between 5 and 30°, between 5 and25°, between 5 and 20°). Frustoconical portion 107 may begin where theimplant thread(s) end and continue in the coronal direction CD tocoronal end 104. Alternatively, coronal region 101 need not includefrustoconical portion 107 and the implant thread(s) may end at coronalend 104 or there may be a portion of coronal region 101 extending beyondthe end of the thread(s) that has a constant diameter or a shape otherthan frustoconical.

Coronal region 101 of implant 100 may include one or more channelsarranged in the form of one or more concave rings 108. Concave rings 108may at frustoconical portion 107 and, illustratively, there are threeconcave rings 108. Concave rings 108 may have a ratio between the radiusof the concave ring and the depth of concavity of the concave ring beingof about 2:1, 3:1, 4:1, 5:1, or 6:1.

Implant 100 also may include prosthetic interface 109 at coronal region101. Prosthetic interface 109 is configured to couple to a prosthetic(e.g., abutment, crown, bridge) directly or via another component, suchas an abutment. Prosthetic interface 109 may be within implant 100 andengaged through coronal end 104, as illustrated in FIG. 1A, or may bepartially or fully exposed, for example, in a one-piece configuration,as discussed below. Prosthetic interface 109 may take any form suitablefor engaging a prosthetic such as, for example, conical, hexagonal, andoctagonal, used in conjunction or separately. Prosthetic interface 109is also configured to minimize relative movement, in particular rotationmotion, between implant 100 and the prosthetic coupled thereto.

In FIG. 1A, prosthetic interface 109 includes Morse Taper connection 110associated with internal polygon 111 (illustratively a hexagon) forengaging the prosthetic. Prosthetic interface 109 may also includeinternal threads 112 to fix to corresponding threads in the prosthetic.Prosthetic interface 109 may be temporarily coupled to an installationtool, such as a transfer piece, screw driver, and/or drill, forinstalling implant 100 within bone.

Implant 100 preferably includes at least one thread extending aroundcore 103 in a plurality of turns from coronal region 101 to apicalregion 102. As is clear in FIG. 1A, the thread(s) may extend fromcoronal region 101 to apical region 102 even though the entire coronalregion 101 and/or the entire apical region 102 need not be threaded. Thethread(s) is preferably self-drilling and need not include aself-tapping structure such as a bone tap. In a self-drilling design,implant 100 is configured to drill itself into biological material,although a predrilled bore hole may be used to assist with startinginsertion of implant 100 into the biological material. In addition, asexplained below, the thread(s) may have one or more notches to removebone (e.g., dense/hard bone) during installation (e.g., bycounter-torqueing).

Illustratively, implant 100 has first thread 113 and second thread 114each extending around core 103 in a plurality of turns from coronalregion 101 to apical region 102. First thread 113 and second thread 114are counterposed to form a double-thread configuration such that one360° rotation of implant 100 causes two ridges of implant 100 to beinserted (e.g., past one turn from first thread 113 and one turn fromsecond thread 114). First thread 113 has turns 115, 116, 117, 118, and119 each formed by a 360° rotation of first thread 113 around core 103.Second thread 114 has turns 120, 121, 122, 123, and 124 each formed by a360° rotation of second thread 114 around core 103. As will be readilyapparent to one skilled in the art, the number of thread(s) on implant100 may be selected based on the desired number of rotations required toinstall implant 100. While implant 100 illustratively has first thread113 and second thread 114, the implants provided herein could have asingle thread, a triple thread, a quadruple thread, etc.

Implant 100 has length 125 and preferably has diameters that varythroughout length 125 configured to reduce removal of biologicalmaterial (e.g., bone, blood vessels within the bone) as compared to aconventional implant. Length 125 is selected according to the biologicalspace available for insertion. For example, length 125 may be a suitablelength for insertion in the jawbone.

Preferably, the thread(s) of the implant has an outer diameter(s) thatincreases in the coronal direction CD from the beginning of thethread(s) at or near apical end 105 and then the thread(s) outerdiameter(s) is constant for a portion of the implant (e.g., at least 20%of length 125 of implant 100, at least 25% of length 125 of implant 100,at least 30% of length 125 of implant 100, at least 35% of length 125 ofimplant 100, at least 40% of length 125 of implant 100, at least 45% oflength 125 of implant 100, at least 50% of length 125 of implant 100, atleast 55% of length 125 of implant 100, at least 60% of length 125 ofimplant 100) to reduce removal of biological material. In at least oneembodiment, the outer diameter(s) of the thread(s) becomes constant atabout the midpoint of length 125 of implant 100. As compared to aconventional implant, which generally has an increasing outer diameterof the thread(s) in the coronal direction throughout the length of thethreads, the thread(s) described herein are configured to reduce theremoval of biological material (e.g., bone, blood vessels within thebone) during implant installation by increasing the opening diameterwithin the bone for only a portion (e.g., a conical portion) of thethreaded area of the implant, thereby decreasing the amount of biologicmaterial removed during the installation, providing increased stability,and reducing healing time.

As shown in FIG. 1A, core 103 has core outer diameter 126 that maydecrease at core diameter decrease rate 127 in the apical direction ADtowards apical end 105. For example, core outer diameter 126 may begreatest in coronal region 101 and smallest in apical region 102. In oneembodiment, core outer diameter 126 is greatest at the most apical endof frustoconical portion 106 and smallest at or adjacent to apical end105. Core diameter decrease rate 127 may decrease at an angle relativeto longitudinal axis 128. The angle is preferably acute and may bebetween 1 and 60°, between 1 and 45°, between 1 and 30°, between 5 and30°, between 5 and 25°, between 5 and 20°, between 1 and 20°, between 1and 15°, between 15 and 15°. The angle may be constant such that corediameter decrease rate 127 remains constant from coronal region 101 toapical region 102.

The thread(s) of implant 100 has thread outer diameter 129 that may beconfigured to define cylindrical portion 130 and conical portion 131.Cylindrical portion 130 is more in the coronal direction CD than conicalportion 131 along implant 100. In cylindrical portion 130, thread outerdiameter 129 preferably remains constant for more than one turn aroundcore 103. Cylindrical portion 130 may be positioned at least partiallyin coronal region 101. Thread outer diameter 129 in cylindrical portion130 may be equal to thread outer diameter 129 at the most coronal partof conical portion 131. In conical portion 131, thread outer diameter129 preferably decreases at thread diameter decrease rate 132 in theapical direction AD. Conical portion 131 may be positioned at leastpartially in apical region 102. Thread diameter decrease rate 132 maydecrease at a lesser rate, the same rate, or at a greater rate than corediameter decrease rate 127. As illustrated, thread diameter decreaserate 132 decreases at a greater rate than core diameter decrease rate127. Thread diameter decrease rate 132 may decrease at an angle relativeto longitudinal axis 128. The angle is preferably acute and may bebetween 1 and 60°, between 1 and 45°, between 1 and 30°, between 5 and30°, between 5 and 25°, between 5 and 20°, between 1 and 20°, between 1and 15°, between 15 and 15°. The angle may be constant such that threaddiameter decrease rate 132 remains constant in conical portion 131. Asillustrated, thread diameter decrease rate 132 is greater than corediameter decrease rate 127 throughout the entire conical portion 131.

Cylindrical portion 130 and conical portion 131 may meet at inflectionpoint 133 where thread outer diameter 129 transitions from constant todecreasing towards apical end 105. Inflection point 133 may be at themidway point along length 125 of implant 100 or within 10%, 20%, or 30%of the midway point of implant. On implant 100, the ratio of the lengthof conical portion 131 to length 125 of implant 100 may range from 1:3to 2:3, and preferably is 1:2.

The difference between core outer diameter 126 and thread outer diameter129 may be greatest at inflection point 133 and the difference betweendiameters 126, 129 may decrease in the coronal direction CD (e.g., frominflection point 133) in cylindrical portion 130 (e.g., throughout theentire cylindrical portion 130). For example, in cylindrical potion 130,the difference between core outer diameter 126 and thread outer diameter129 may be greatest at the most apical point of cylindrical portion 130and smallest at the most coronal point of cylindrical portion 130. Thedifference between core outer diameter 126 and thread outer diameter 129may decrease in the apical direction AD (e.g., from inflection point133) in conical portion 131 (e.g., throughout the entire conical portion131). For example, in conical potion 131, the difference between coreouter diameter 126 and thread outer diameter 129 may be greatest at themost coronal point of conical portion 131 and smallest at the mostapical point of conical portion 131. The difference between core outerdiameter 126 and thread outer diameter 129 may be proportional at theturn closest to coronal end 104 to the difference between core outerdiameter 126 and thread outer diameter 129 at the turn closest to apicalend 105.

In FIG. 1A, cylindrical portion 130 includes turns 118 and 119 of firstthread 113 and turns 123 and 124 of second thread 114 while conicalportion 131 includes turns 115, 116, and 117 of first thread 113 andturns 120, 121, and 122 of second thread 114.

Referring now to FIGS. 1B and 1C, additional details on the thread(s)and notches within the thread(s) are shown. Preferably, the thread(s)have a plurality of notches spaced radially and longitudinally from oneanother along the implant. As compared to a conventional bone tap, whichis a continuous cut through a plurality of turns of the thread(s), thenotches described herein are configured to permit selective removal ofbone (e.g., dense/hard bone) during implant installation. For example,the notches may be used to cut bone (including dense/hard bone) throughapplication of counter-torque force to the bone. A dentist/surgeon mayrotate the implant in a direction opposite the installation directionsuch that one or more notches cuts through the bone at a partialinstallation position (e.g., when dense/hard bone is encountered) topermit further installation.

One or more of the curved notches may be partially notched to reflect aportion of a semi-spherical surface and/or may be partially notched toreflect a portion of a semi-cylindrical surface. The semi-sphericalsurface may intersect the semi-cylindrical surface at each notch. One ormore of the curved notches may define a cutting edge at the respectivenotch, e.g., where the semi-spherical surface of the notch meets thethread outer diameter surface. One or more of the curved notches alsomay define an opposing edge, opposite the cutting edge, at therespective notch, e.g., where the semi-cylindrical surface of the notchmeets the thread outer diameter surface. In a preferred embodiment, eachcurved notch of the implant defines a cutting edge, where a partiallysemi-spherically curved portion of the notch meets the outer surface ofthe thread, and an opposing edge, where a partially semi-cylindricallycurved portion of the notch meets the outer surface of the thread.

In FIG. 1B, curved notches 140, 141, 142, 143, 144, 145, and 146 arenotched into the thread(s) over a plurality of turns. Curved notches140, 141, 142, 143, 144, 145, and 146 are spaced apart from one anotherradially and longitudinally along the length of the thread(s). As shown,curved notch 141 is notched into turn 122 of second thread 114, curvednotch 142 is notched into turn 117 of first thread 113, and curved notch143 is notched into turn 121 of second thread 114. Unlike a conventionalbone tap, the curved notches need not substantially overlap with oneanother in the coronal direction CD and/or the apical direction AD. Forexample, curved notch 142 does not substantially overlap with curvednotch 141, which is on a turn adjacent in the coronal direction CD(illustratively, immediately adjacent), and curved notch 142 does notsubstantially overlap with cured notch 143, which is on a turn adjacentin the apical direction AD (illustratively, immediately adjacent). “Doesnot substantially overlap” as described herein means that the notches donot overlap: by more than 50% the width 147 of the notch, by more than40% the width 147 of the notch, by more than 30% the width 147 of thenotch, by more than 25% the width 147 of the notch, by more than 20% thewidth 147 of the notch, by more than 15% the width 147 of the notch, bymore than 10% the width 147 of the notch, by more than 5% the width 147of the notch, and/or do not overlap. For example, if a notch has a widthof 10 mm and the notch does not substantially overlap another notch bymore than 10% the width, than at most 1 mm of the 10 mm width canoverlap with the adjacent notch in the coronal direction CD or theapical direction AD. That notch could also overlap by, at most, 1 mmwith the adjacent notch in the other direction (coronal or apical). Acurved notch may overlap minimally at its cutting edge side with anadjacent notch at its opposing edge side and the curved notch mayoverlap minimally at its opposing edge side with a different adjacentnotch at its cutting edge side.

Referring still to FIG. 1B, curved notch 142 is shown as havingsemi-spherical face 148, where curved notch 142 is partially notched toreflect a portion of a semi-spherical surface, and semi-cylindrical face149, where curved notch 142 is partially notched to reflect a portion ofa semi-cylindrical surface. The semi-spherical face may intersect thesemi-cylindrical face at each notch. Curved notch 142 defines cuttingedge 150 where semi-spherical face 148 meets the thread outer diametersurface. Cutting edge 150 is positioned on the thread such that cuttingedge 150 contacts biological material (e.g., bone, blood vessels withthe bone) before other portions of the notch. Cutting edge 150 isconfigured to cut through the biological material (e.g., preferablyincluding dense/hard bone) during installation when counter-torqueaction is applied to the implant (e.g., screwing in the counterclockwisedirection opposite the installation direction). Cutting edge 150 mayalso cut through biological material during removal or adjustment ofimplant 100, e.g., during unscrewing in the counterclockwise direction,by cutting through biological material. Curved notch 142 also definesopposing edge 151, opposite cutting edge 150 of notch 142, wheresemi-cylindrical face 149 meets the thread outer diameter surface.

Use of a curved notch(es) with a semi-spherical face and asemi-cylindrical face enhances cutting during counter-torqueing,adjustment, and/or removal of the implant and enhances integrity of thethreads. Semi-spherical face 148 may intersect with semi-cylindricalface 149 at intersection point 152 of curved notch 142. Intersectionpoint 152 may be at the midway point of the width of the notch. Thesemi-spherical face of the notch(es) may be notched into the thread(s)with a spherical end of an machining tool to mill the surface to reflecta portion of a semi-spherical surface.

The curved notch(es) may be inclined relative to longitudinal axis 128of implant 100. In FIG. 1B, centerline 153 runs through the center ofcurved notch 143 and is inclined at the angle of the thread. Curvednotch 143 is inclined between centerline 153 and longitudinal axis 128at notch inclination angle 154 (e.g., between 65 and 135°, between 65and 115°, between 90 and 135°, between 90 and 115°, between 100 and125°, between 100 and 115°).

The curved notch(es) may be radially distributed from adjacent notches(e.g., on the same thread or a different thread) at distribution angles,using longitudinal axis 128 as a central pivot point. For example, acurved notch may be distributed at a distribution angle (e.g., between30 and 180°, between 60 and 180°, between 30 and 120°, between 60 and120°, between 90 and 180°) from its adjacent notch (e.g., immediatelyadjacent) in the coronal and/or apical direction. In addition, thecurved notch(es) may be angled relative to adjacent notches (e.g., onthe same thread or a different thread) at notch angles, usinglongitudinal axis 128 as a central pivot point. For example, a curvednotch may be angled at a notch angle (e.g., between 10 and 80°, between20 and 60°, between 30 and 60°, between 35 and 55°, 45°) from itsadjacent notch (e.g., immediately adjacent) in the coronal and/or apicaldirection.

Referring now to FIG. 1C, a cross-sectional view of implant 100 alongline AA in FIG. 1B is shown. Curved notch 145 has semi-spherical face155 defining cutting edge 156 and semi-cylindrical face 157 definingopposing edge 158. Curved notch 146 has semi-spherical face 159 definingcutting edge 160 and semi-cylindrical face 161 defining opposing edge162. To facilitate cutting during counter-torqueing, adjustment, and/orremoval, the semi-spherical face(s) of the notch(es) may have a portionof the normal vectors pointing with a deviation angle in the oppositedirection of implant installation direction 163. As shown at curvednotch 145, semi-spherical face 155 has a portion (e.g., at least 5%, atleast 10%, at least 20%, at least 30%, at least 40%, at least 50%) ofnormal vectors 164 pointing with a deviation angle (e.g., between 1 and15°, between 1 and 10°, between 5 and 15°, between 5 and 15°, up to 15°)the opposite direction of implant installation direction 163. Cuttingedge 156 may cut biological material in an opposite direction related tothe direction of installation 163 due to a concentration of normalvectors 164 at semi-spherical face 155 near and on cutting edge 156, asseen in FIG. 1C. As shown at curved notch 146, semi-cylindrical face 161may be in the form of a substantially straight line 165 parallel to thetangent line of the outer face of the thread, wherein the tangent linematches cutting edge 160. Semi-cylindrical face 161 may be perpendicularto where cutting edge 160 meets the outer thread surface at center axis166.

FIG. 1D shows a close-up view of a curved notch (illustratively curvednotch 142) that may be incorporated in the thread(s) of the implantsdescribed herein. A curved notch may have two curved faces of differinggeometries that may intersect at the deepest point of the curve anddefine cutting and opposing edges at the outer ends of the notch. Asdescribed above, the differing geometries may be a semi-spherical facethat reflects a portion of a surface of a semi-sphere and asemi-cylindrical face that reflects a portion of a surface of asemi-cylinder. In FIG. 1D, curved notch 142 includes semi-spherical face148 that defines cutting edge 150 and semi-cylindrical face 149 thatdefines opposing edge 151. Semi-spherical face 148 and semi-cylindricalface 149 meet at intersection point 152. Semi-cylindrical face 149 mayreflect a portion of semi-cylindrical surface where the semi-cylinder islaying lengthwise such that apical edge 167 and coronal edge 168 ofcurved notch 142 are straight at semi-cylindrical face 149.Semi-cylindrical face 149 may curve inward from apical edge 167 and fromcoronal edge 168 to reflect a portion of a semi-cylindrical surface. Insemi-spherical face 148, apical edge 167 and coronal edge 168 are curvedto reflect a portion of a semi-spherical surface. Semi-spherical face148 may curve inward from apical edge 167 and from coronal edge 168 toreflect a portion of a semi-spherical surface.

Referring now to FIG. 1E, core 103, frustoconical portion 106,prosthetic interface 109, and first and second threads 113, 114 ofimplant 100 are shown separated from one another for illustrativepurposes. Core outer diameter 126 and thread outer diameter 129 areshown at parts adjacent the apical end of implant 100.

Referring to FIG. 1F, a thread design that may be used in implant 100 isshown. Each cross section of the thread has a coronal face, an outerface, an apical face, and a height. For example, the thread at the turnimmediately adjacent inflection point 133 in the coronal direction CDhas coronal face 170, outer face 171, apical face 172, height 173, andbase width 174. Height 173 is the distance between core 103 and outerface 171 at that turn. Base width 174 is the distance between coronalface 170 and apical face 172 where the faces meet core 103. Thread widthis the distance between coronal face 170 and apical face 172 at outerface 171. As another example, the thread at the turn immediatelyadjacent inflection point 133 in the apical direction AD has coronalface 175, outer face 176, apical face 177, height 178, and base width179. Height 178 is the distance between core 103 and outer face 176 atthat turn. Base width 179 is the distance between coronal face 175 andapical face 177 where the faces meet core 103. Thread width is thedistance between coronal face 175 and apical face 177 at outer face 176.

Implant 100 may have variable thread heights and/or variable threadwidths. For example, the thread height may be greater at turns adjacentinflection point 133 than turns adjacent the coronal and apical ends.The thread width may be greater at turns adjacent the coronal and apicalends than turns adjacent inflection point 133.

FIGS. 1G, 1H, and 1I show top, isometric, and side views, respectively,of implant 100. In FIGS. 1G, 1H, and 1I, prosthetic interface 109includes a Morse Taper connection associated with internal polygon 111(illustratively a hexagon) for engaging the prosthetic. For implant 100,the length may be considered as from the apical end to the coronal endincluding the back taper.

Referring now to FIGS. 2A, 2B, and 2C, implant 100′ is constructedsimilarly to implant 100 of FIGS. 1A to 1I, wherein like components aredefined by like-primed reference numbers. Thus, for example, firstthread 113 of FIGS. 1A to 1I corresponds to first thread 113′ of FIGS.2A, 2B, and 2C. As will be observed by comparing FIGS. 1G, 1H, and 1I toFIGS. 2A, 2B, and 2C, implant 100′ has two concave rings 108′ instead ofthree concave rings in the coronal region.

Referring now to FIGS. 3A, 3B, and 3C, implant 100″ is constructedsimilarly to implant 100 of FIGS. 1A to 1I, although implant 100″ has amodified prosthetic interface. Implant 100″ has prosthetic interface 300with external polygon 301 (illustratively a hexagon) for engaging theprosthetic, rather than an internal polygon. For implant 100″, thelength may be considered as from the apical end to the coronal end ofthe implant, including the external polygon.

Referring now to FIGS. 4A, 4B, and 4C, implant 100′″ is constructedsimilarly to implant 100 of FIGS. 1A to 1I, although implant 100′″ has amodified prosthetic interface. Implant 100′″ has prosthetic interface400 for engaging the prosthetic in a one-piece type configuration.Prosthetic interface 400 is adapted to directly couple to the prostheticcrown or bridge, without the need for an intermediate element (e.g., anabutment) and thus preventing coupling between two parts in the sub-gumsregion. Prosthetic interface 400 may be shaped as a cylinder 401, whoseouter diameter may vary although the maximum outer diameter of cylinder401 is preferably less than or equal to the maximum thread outerdiameter of the implant. For implant 100′″, the length may be consideredas from the apical end to the coronal end of the concave rings. As willbe observed by comparing FIGS. 4B and 4C, implant 100′″ may or may notinclude concave rings 108′″. When implant 100′″ does not include concaverings 108′″, the length may be considered as from the apical end to theend of the threads.

The implants provided herein may be made from a biocompatible metal(s),such as titanium and alloys thereof, and may be coated with other typesof biocompatible materials, such as hydroxyapatite, and/or receive asurface treatment in order to improve the osseointegration quality ofthe implant surface(s).

Provided herein are methods of inserting the implants described abovewithin bone. In accordance with one aspect, a method may includepositioning an apical end of the implant at a desired location of thebone (e.g., at a predrilled bore hole in the jawbone where a prostheticis to be placed to replace one or more teeth). The implant may have atleast one thread extending around a core of the implant in a pluralityof turns. The at least one thread may have a plurality of curved notcheseach defining a cutting edge where a partially semi-spherically curvedportion of the notch meets the outer surface of the at least one thread.The method may further include rotating the implant (e.g., clockwise)such that the at least one thread cuts the bone contacted by the atleast one thread to enlarge an opening in the bone as the implant isscrewed into the bone. The at least one thread may have a self-drillingconfiguration (e.g., where the thread(s) begins at or adjacent theapical end of the implant) to compress bone as the implant is installed.During installation, the method may include applying a counter-torque byrotating the implant in the opposite direction (e.g., counterclockwise)to cut bone with at least one cutting edge. Such counter-torque rotationmay be especially advantageous for removing dense/hard bone tissueencountered during installation. For example, the dentist/surgeon mayapply the counter-torque to cut and remove the hard/dense bone materialat a partial installation position before reaching the desired, fullinstallation depth in the bone because, for example, the implant becomesstuck during installation. After counter-torque rotation, the method mayinclude rotating the implant in the installation direction (e.g.,clockwise) to complete installation. The method may also includerepeating counter-torque rotation during installation at the same depthor a different depth(s) as the depth of the first counter-torquerotation. After installation, a prosthetic (e.g., crown, abutment,bridge) may be coupled to the implant directly or via an intermediateelement such as an abutment.

In accordance with another aspect, a method may include positioning anapical end of the implant at a desired location of the bone (e.g., at apredrilled bore hole in the jawbone where a prosthetic is to be placedto replace one or more teeth). The implant may include at least onethread extending around a core of the implant in a plurality of turns.The at least one thread may have a thread outer diameter configured todefine a cylindrical portion and a conical portion formed more apicallythan the cylindrical portion along a length of the implant. The methodmay further include rotating the implant such that the conical portionof the at least one thread increases an opening diameter in the bone asthe conical portion enters the bone until the conical portion is fullyscrewed into the bone. The method also may include continuing to rotatethe implant such that the cylindrical portion of the at least one threadenters the bone without increasing the opening diameter in the bone. Thecylindrical portion outer diameter may be equal to the maximum outerdiameter of the conical portion. In addition, the cylindrical portionmay be formed along at least, for example, 25% of the length of thethread.

Definitions

Unless otherwise defined, each technical or scientific term used hereinhas the same meaning as commonly understood by one of ordinary skill inthe art to which this disclosure belongs. In accordance with the claimsthat follow and the disclosure provided herein, the following terms aredefined with the following meanings, unless explicitly stated otherwise.

The term “about” or “approximately,” when used before a numericaldesignation or range (e.g., pressure or dimensions), indicatesapproximations which may vary by (+) or (−) 5%, 1% or 0.1%.

As used in the specification and claims, the singular form “a”, “an” and“the” include both singular and plural references unless the contextclearly dictates otherwise. For example, the term “a thread” mayinclude, and is contemplated to include, a plurality of threads. Attimes, the claims and disclosure may include terms such as “aplurality,” “one or more,” or “at least one;” however, the absence ofsuch terms is not intended to mean, and should not be interpreted tomean, that a plurality is not conceived.

As used in the specification and claims, “at least one of” meansincluding, but not limited to, one or more of any combination of thefollowing. For example, “at least one of A, B, and C” means including,but not limited to, A(s) or B(s) or C(s) or A(s) and B(s) or A(s) andC(s) or B(s) and C(s) or A(s) and B(s) and C(s); none of which excludesother elements such as D(s), E(s), etc.

As used herein, the term “comprising” or “comprises” is intended to meanthat the devices, systems, and methods include the recited elements, andmay additionally include any other elements. “Consisting essentially of”shall mean that the devices, systems, and methods include the recitedelements and exclude other elements of essential significance to thecombination for the stated purpose. Thus, a device or method consistingessentially of the elements as defined herein would not exclude othermaterials or steps that do not materially affect the basic and novelcharacteristic(s) of the claimed invention. “Consisting of” shall meanthat the devices, systems, and methods include the recited elements andexclude anything more than a trivial or inconsequential element or step.Embodiments defined by each of these transitional terms are within thescope of this disclosure.

While various illustrative embodiments of the invention are describedabove, it will be apparent to one skilled in the art that variouschanges and modifications may be made therein without departing from theinvention. The appended claims are intended to cover all such changesand modifications that fall within the true scope of the apparatus andmethods of the present invention.

What is claimed:
 1. A method of installing a dental device in a jawbone,the method comprising: positioning an apical end of an implant at adesired location of the jawbone, the implant comprising a threadextending around a core of the implant in a plurality of turns from acoronal region to an apical region of the implant, the thread comprisinga curved notch defining a cutting edge and an opposing edge opposite thecutting edge; rotating the implant in an installation direction to screwthe implant into the jawbone using the thread; applying a counter-torqueby rotating the implant in an opposite direction to cut the jawbone withthe cutting edge; and after applying the counter-torque, rotating theimplant in the installation direction to a full installation depth inthe jawbone, wherein the curved notch is curved such that aconcentration of normal vectors opposite the installation direction arelocated on and adjacent to the cutting edge to facilitate cutting thejawbone with the cutting edge while applying the counter-torque, whereinthe curved notch has a semi-spherical face that intersects with asemi-cylindrical surface and the curved notch is formed such that theconcentration of normal vectors is at the semi-spherical face.
 2. Themethod of claim 1, wherein the thread has a self-drilling configuration,and wherein rotating the implant in the installation direction comprisescutting the jawbone with the thread to compress the jawbone as theimplant is installed.
 3. The method of claim 1, further comprisingrepeating applying the counter-torque by rotating the implant in theopposite direction at a different depth within the jawbone.
 4. Themethod of claim 1, further comprising, after rotating the implant in theinstallation direction to the full installation depth, coupling a crownor a bridge to the implant.
 5. The method of claim 4, further comprisingcoupling an abutment to the implant, and wherein coupling the crown orthe bridge to the implant comprises coupling the crown or the bridge tothe abutment.
 6. The method of claim 1, further comprising drilling abore hole in the jawbone before positioning the apical end of theimplant at the desired location, wherein the desired location of thejawbone is at the bore hole.
 7. The method of claim 1, wherein theimplant further comprises a second thread such that the thread and thesecond thread extend around the core in a double-thread configuration.8. The method of claim 1, wherein the thread has a plurality of curvednotches each defining a respective cutting edge, the plurality of curvednotches spaced radially and longitudinally from one another.
 9. Themethod of claim 1, wherein the opposing edge does not cut the jawbonewhile rotating the implant in the installation direction and whileapplying the counter-torque.
 10. The method of claim 8, wherein a firstcurved notch of the plurality of curved notches on a first turn does notoverlap with a second curved notch on a second turn by more than 10% awidth of the first curved notch at one side of the first curved notch,the second turn being adjacent the first turn in a coronal direction.